An Electrosynthesis of 1,3,4‐Oxadiazoles from N‐Acyl Hydrazones

The 1,3,4‐oxadiazole is a widely encountered motif in the areas of pharmaceuticals, materials, and agrochemicals. This work has established a mediated electrochemical synthesis of 2,5‐disubstituted 1,3,4‐oxadiazoles from N‐acyl hydrazones. Using DABCO as the optimal redox mediator has enabled a mild oxidative cyclisation, without recourse to stoichiometric oxidants. In contrast to previous methods, this indirect electrochemical oxidation has enabled a broad range of substrates to be accessed, with yields of up to 83 %, and on gram scale. The simplicity of the method has been further demonstrated by the development of a one‐pot procedure, directly transforming readily available aldehydes and hydrazides into valuable heterocycles. The indirect electrochemical oxidative cyclisation of N‐acyl hydrazones offers an efficient approach to access 1,3,4‐oxadiazoles, an important motif in medicinal chemistry. The DABCO‐mediated reaction enables the selective synthesis of a broad range of these valuable heterocycles from readily available aldehydes and hydrazides.